


Nature Vs. Nurture

by Levi__Acker_Gay, orphan_account



Category: Shadowhunters (TV), The Mortal Instruments Series - Cassandra Clare
Genre: Alec is raised in the Mundane world, Artist Clary Fray, Athlete Sebastian and Alec, Confusion, Dancer Alec Lightwood, F/M, Family Secrets, Good Jonathan Christopher Morgenstern | Sebastian Verlac, Implied/Referenced Self-Harm, It's only in the Shadow world, M/M, Magnus Bane is Powerful, Non-Traditional Alpha/Beta/Omega Dynamics, Sebastian/Jonathan raised in the mundane world, Secrets, Student Clary Alec Sebastian and Simon, very lightly mentioned, with Clary
Language: English
Status: In-Progress
Published: 2020-06-07
Updated: 2020-06-07
Packaged: 2021-03-02 22:33:58
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,024
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24444394
Author URL: https://archiveofourown.org/users/Levi__Acker_Gay/pseuds/Levi__Acker_Gay, https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: The club was full of dry ice smoke. Colored lights played over the dance floor, lightning up the dancing writhing bodies, turning it into a multicolored fairyland of blues and acid greens."So," Simon said, "pretty good music, eh?"Clary didn't reply. They were dancing, or what passed for it - a lot of swaying back and forth, and small jumps.OR...A fanfiction based on Jocelyn being a good mother, and rescuing her son Sebastian from Valentine, by raising him alsongside Alec and Clary in the mundane world.
Relationships: Alec Lightwood & Jonathan Christopher Morgenstern | Sebastian Verlac, Clary Fray & Alec Lightwood, Clary Fray & Jonathan Christopher Morgenstern | Sebastian Verlac, Clary Fray & Simon Lewis, Clary Fray/Jace Wayland, Magnus Bane/Alec Lightwood, Simon Lewis & Alec Lightwood, Simon Lewis & Jonathan Chrisopher Morgenstern | Sebastian Verlac
Comments: 12
Kudos: 47





	Nature Vs. Nurture

**Author's Note:**

> For Nadja_Lee, whose work, Redefining Family inspired this. I totally recommend checking that fic out.  
> Hope you enjoy reading it.  
> Sorry for any mistakes made.  
> Based on the book City of bones

The club was full of dry ice smoke. Colored lights played over the dance floor, lightning up the dancing writhing bodies, turning it into a multicolored fairyland of blues, purples and acidic greens.  
"So," Simon said, "pretty good vibe, eh? I'm glad we came, are you?" Clary didn't reply. They were dancing, or what passed for it - it consisted of a lot of swaying back and forth, and small jumps. Awkward. At that moment, Clary wished she had her brother, Alec's elegance and grace, his dancing was always amazing, especially compared to his usual clumsiness outsie of the studio where he practices.

She watched her eldest brother, Alec, flirting with a guy with dark blue hair, just a few shades darker then Alec's eyes. The guy who who had talked his way into the club. Sebastian she had lost ages ago, he had said he was going to get drinks, and had never returned. Though Clary wasn't really paying much to her immediate surroundings, her eyes were on the blue-haired boy. He stood with his hand on her brother, Alec's chest. 'Oh well, usually Seb attracted the hot ones, but Alec could, when they managed to get him in anything beside his usual ratty sweaters' she thought glumly. No one paid her any attention, she was so short, so people overlooked her. Literally.

Suddenly, Clary felt a hand clamp down on her shoulder. She whirled, almost hitting a boy dancing nearby. The boy shot her an evil look. "Sorry-sorry!" she said in his direction. Clary turned to see Sebastian. She grinned up at him, wondering where he had disappeared to, but she knew better then to ask him. "What?!" she shouted instead, trying to be heard over the pounding music. He said something but she couldn't hear him, nor make out what he was saying in the gloom. She pointed to her ear and shouted again. "I can't hear you!"

Sebastian just rolled his dark eyes and handed her a drink. He ran a hand through his tousled blond hair. His light blue shirt pasted to him like a second skin left nothing to the imagination. Clary was surprised no one was with him. She could just about make out him saying something about the drink being non-alcoholic, what with her being a child and all. Simon waved down Alec, who reluctantly parted from the dark blue-haired boy Clary had been eyeing, and he had been flirting with. She watched the boy turn and walk away, seeming to have already forgotten about Alec. She watched him make his way across the club, while Alec began shoving his way through the crowd, only half-listning to her brother and Simon. The blue-haired boy straightned up suddenly, snapping to attention like a hunting dog on point.

Clary followed his line of sight, and saw the girl in the crimson dress. 'Oh well,' Clary thought, trying not to feel like a popped balloon. The girl was gorgeous, tall and ribbon slim, the kind she would have liked to drawn and look like.

"I feel," Simon said, trying to get her attention, "that this evening, the DJ is doing an exceptional job. Don't you agree?" Clary rolled her eyes, Simon hated this type of club music. Her attention however, remained on the girl in the crimson dress. Through the darkness and artificial fog, her red dress shone. 'No wonder the blue-haired boy was following her, too distracted to notice anything else around him - even the dark shape hard on his heels, weaving through the crowd after him. Clary slowed her dancing and stared, she could just make out that the shape was a boy, tall and wearing dark clothes. A small butterfly of apprehension began to flutter in her chest.

"Meanwhile," Simon added, "I want to tell you that i've been cross-dressing. Also, I'm sleeping with your mom. I thought you should know." This earned a whack from Sebastian, before he started lecturing Simon. Alec bent down and whispered into her ear, "are you okay Clary? You seem distracted" he said, his breath brushing against her overly warm skin, disturbing her red locks. She just shook her head in response.

The girl had reached the wall, and was opening a door that had STORAGE across the front. She beckoned the blue-haired boy after her, and they slipped through the door. It wasn't anything she hadn't seen before, a couple sneaking off to dark corners of the club to make out - but that made it even stranger that they were being followed.  
Clary raised herself up onto tip-toe, trying to see over the crowd. The guy who had been following them had stopped at the door, and she could see he was blond, though darker than her brother's almost white hair, kind if a more honey color. He reached into his dark jacket and drew out something long and sharp that flashed under the strobing pulsing lights. A knife.

"Alec!" Clary shouted, seizing his arm. Her shout caught the attention of Sebastian and Simon as well, who crowded in around her.  
"Do you see that guy?" she pointed widely, "by the door, it's marked storage." Alec, following her wild gesture, nodded, frowning slightly. Simon squinted and shrugged. "I don't see anything."  
"The guy pulled out a knife." Clary exclaimed, breathing hard.  
Suddenly all buisness, Simon squared his shoulders. "I'll get one of the security guards." He strode away, pushing through the crowds.  
"He just went in" Sebastain said.  
"You stay here" Alec said, looking down at Clary. He then grabbed Sebastian's arm and hauled him away, heading towards the storage room.

Clary glanced at Simon's slowly retreating back, and then forward, after her brothers. 'By the time Simon got back with the security something terrible might have already happened.' Biting hard on her bottom lip, Clary started to push her way through the crowd after her brothers.

.........................................................................................................................................................................................................................

Alec pushed open the door to the storage room slowly, Sebastian hot on his heels. For a moment he thought the room was deserted. The only windows were high up, tiny and barred; faint street noises came through: the sound of honking car horns, and screeching tyres. 'There's no one here,' he realized, looking around the room in bewilderment. He glanced behind him, at Sebastian - and heard voices. A laugh, and a boy answering sharply. When he turned back round, and saw them.  
It was as if they had bounced into existence between one blink of an eye and the next.  
Sebastian heard the door open behind him again; thinking it was Simon with the security, he turned, but it was Clary. He tugged at Alec's sleeve, who turned sharply, and when he saw Clary, he sighed, shoulders slumping.

...............................................................................................................................................................................................................................

Clary saw the girl with the blood colored dress, her dark and slightly curled hair hanging down her back like rope. The boy was with her, his blond hair gleaming like brass in the light coming through the high window. He stood with his hands in his pockets, facing the punk kid, who was tied to a pillar with wire; his hands stretched behind him, his legs bound at the ankles. His face pulled tight with pain.

.....................................................................................................................................................................................................................................

Heart hammering in his chest, Alec ducked behind the nearest concrete pillar, pulling Sebastain and Clary after him. He was surprised they hadn't been spotted yet. They watched as the fair-haired boy paced back and forth, his arms now crossed across his chest. "So," he said, "you still haven't said if there are any others of your kind here with you?"

'Your kind?' Alec wondered, what he was talking about. 'Maybe they had stumbled across some kind of gang war. Whatever it was, it was dangerous, and they needed to get out of there.' Before he could formulate a plan to get out, the cute blue-haired boy spoke, "I don't know what you're talking about," his tone pained, but surly. "He means other demons," the girl spoke. "You do know what a demon is, don't you?" she asked with a smirk. The boy tied to the pillar turned his face away, his mouth working.

"Demons," drawled the blond. 'They're crazy' Alec thought, pushing Clary behind him as she tried to look around the pillar, 'actually crazy.'

"Religiously defined as hell's denizens, the servant of Satan, but understood by the Clave, to be any malevolent spirit whose origin is outside-" "That's enough, Jace" said the girl. "Isabelle thinks I talk too much" he said confidingly. "Do you think I talk too much?" The blue-haired boy didn't respond.

Isabelle tossed her dark hair, "kill it Jace," she said. Jace raised his hand, and Alec saw the dimly light spark off the blade he was holding. It was oddly translucent, sharp as a shard of glass. The hilt set with red stones. The bound boy gasped, "wait. Valentine's back!" he protested, yanking at the bonds that held his hands behind his back. "All the Infernal Worlds know it, I can tell you where he is-"

Rage flared suddenly in Jace's icy gold eyes. "By the Angel, every time we capture one of you bastards, you all claim to know where Valentine is. Well, we know where he is too. He's in hell. And you-" Jace turned the knife in his grasp, "you can join him there." Clary could take no more. She rushed past Sebastian, past Alec, who tried to catch at her.

She stepped out from behind the pillar. "Stop!" she cried. "You can't do this." Jace whirled, so startled that the knife flew from his grasp, and clattered to the concrete floor. Isabelle turned along with him, wearing an identical expression of astonishment. The blue-haired boy hung in his bonds, stunned and gaping. Out of the corner of her eyes, she saw Alec and Sebastian emerge from behind the pillar.

Seeing them, Jace asked cockily "anymore?" which earned a thwack from Isabelle. "A mundie girl, and she can see us," he ignored Alec and Sebastian, who moved to stand next to her. "Of course WE can see you" Sebastian snapped. "We're not blind."

"Oh, but you are," said Jace, turning to look at Sebastian, before bending to pick up his knife. "You just don't know it." He straightened up. "You'd better get out of here, if you know what's good for you." Before Clay could respond, she felt hands on her shoulders, hauling her backwards. "I'M not going anywhere," Alec said, shooting Clary and Sebastian a pointed look. "If I do, you'll kill him," he pointed at the chained boy.

"That's true," admitted Jace, twirling the knife expertly between his fingers, "what do you care if I kill him or not? Mundie" he spat. "Be-because-" Clary spluttered, wrestling the from the grip Sebastian had on her shoulders, "you can't go around killing people."

"You're right," said Jace. "I can't go around killing people." He pointed at the blue-haired boy on the floor. "That's not a person. It may look like a person and talk like a person, maybe even bleed like a person. But it's a monster."  
"Jace" Isabelle warned, "that's enough."  
"You're crazy," Sebastian said from behind Alec. "Come on, let's go." Clary started to back away. "I've called the police. They'll be here any moment."  
"She's lying" said Isabelle, glaring at her. "Jace, do you-" she never got to finish her sentence.

At that moment, the blue-haired boy, with a high yowling cry, tore free of the restraints and flung himslef at Jace.  
Alec grabbed Clary and shoved her behind him. Jace and the boy fell to the ground, and rolled together, the blue-haired boy tearing at Jace with hands that glittered, as if tipped with metal. Isabelle shreiked. The blue-haired boy was sitting on Jace's chest, blood gleaming at the tips of his razorlike claws. Isabelle was running towards them, brandishing a whip in her hand.  
The blue-haired boy slashed at Jace, claws extended. Jace threw up an arm to protect himself, and the claws raked it, splattering blood. The blue-haired boy lunged again - and Alec was there, shoving the boy off with a well placed kick that made the boy fall to the side.  
Clary stared, her brother had just been right next to her: she hadn't seen him move.

Jace rolled over. He sank a gleaming blade into the boy's chest. Blackish liquid exploded around the hilt.  
The boy arched off the floor, gurgling and twisting . Sebastian grabbed Clary by the arm, hauling her away, shouting at Alec to come as well.

The last thing Clary had seen was the boy's body begin to jerk and twist as he crumpled, folding in on himself. Clary scrambled back into Sebastian's grip, feeling sick, as he turned, blocking the sight from her view. They began to move toward the door, but founf their way blocked by Isabelle, whip in hand.  
She flicked it toward's Clary, intendig for it to wrap around her wrist. But Sebastian was faster. His own habdd came down, grabbing the whip, yanking it out of her grip. She gasped, eyes bugging slightly.  
"Stupid little mundie's," Isabelle hissed between clenched teeth. "You could have gotten Jace hurt, or even killed." "He's crazy" Alec said, appearing beside his siblings. "You're both crazy. What do you think you are, vigilante killers? Are you part of a gang? The police will-"  
"The police aren't usually interested, unless you can produce a body," Jace said, clutching his arm.

Clary pulled herslef out of her brothers grip, glancing at the spot where the boy had disapeared. There wasn't even a smear of blood - nothing to show that the boy had even existed. "They return to their home dimensions when they die," Supplied Jace, "In case you were wondering." Isabelle glared at him. "They can see us, Iz" he pondered. "they know too much."

"So what should we do with them?" Isabelle demanded. "Let them go," Jace said quietly. Isabelle shot him a surprised, almost angry look, but didn't argue. She bent to pick the whip off the dusty ground, glaring at Sebastian as she straightened up. "Maybe we should take them to the Institute?" Isabelle suggested, "but they're mundies. Oh, I don't know," she threw her hands up in exhasparation. "Or are they?" Jace said softly. "Have you had dealings with demons? Walked with the warlocks? Talked with the fair-"

"Shut up!" Sebastian interrupted, "we have no idea what you're talking about. We don't believe in- in demons, or whatever you-"

"Clary?" It was Simon's voice, "Alec? Seb?" The three whirled around, Alec almost smacking into a concrete pillar. Clary, in any other situation, would have laughed at his clumsiness, along with Seb and Simon. But this wasn't any normal situation, so she settled for shooting him an amusing glance. Alec flushed red. Simon was standing by the door. One of the burly bouncers, the one Alec had flirted with awkwardly, to let them into the club and skip the line, next to him. Alec flushed even brighter, and ducked his head.

"Are you guy's okay?" he peered at them through the half-darkness, squinting through his glasses. "What happened to the guy who - you know, the one with the knife?" The three siblings stared at him, Alec glancing behind him to see Isabelle and Jace still stood, with an amused look on their face. Jace grinned at him, still clutching the bloody knife, and dropped a half apologaletic, half mocking shrug. Clearly he wasn't surprised that neither Simon nor the bouncer could see them.

'So why could they?'

Slowly, Alec turned back round to face Simon, who was staring at Clary. "I thought they were in here" she said lamely, "but I guess they weren't. Sorry." She glanced at Simon, who looked more embarassed then worried now, to the bouncer who looked annoyed. "It was a mistake," muttered Sebastian, as the bouncer gave Alec a dirty look, making him flush a darker red. 'There goes ever getting back into pandemonium,' he thought glumly.

Behind them, Isabelle giggled.

Alec could picture the smug smjrk on Jace's face. It made him want to punch the guy even more. But they needed to get out.

He could just about make out what Jace and Isabelle were whispering to each other. "Mundie's.... No second gender... Omega... Maybe beta for the boy.... I don't know."  
Alec wondered what on earth they were talking about. 'Alphas and omegas, wasn't that something to do with wolves. Or Simon and Clary's latest anime obsession.' Alec shrugged as they quickly left the storage room, flushing as he passed by the bouncer, who patted him on the but.  
Alec gasped, but was shoved forward by Sebastian, "ignore that bastard" he mumbled into his ear, "he isn't worth it."

........................................................................................... ......................................................................................................................................

Magnus gasped as he saw a familiar hair of red and white-blond pass close to where he was sitting. He could also see two boys with dark hair following behind, one with glasses. They looked very familiar to the warlock, apart from glasses boy.  
His alpha could tell that they had no second gender, as they had no runes. They were essentially like mundanes, with the lack of a second gender. It was a shame that Jocelyn and Luke hid their true heritage from them. But it was a necessary evil. Magnus stood quickly from his seat, handing his glass to a faerie, and made his way through his club, most of the dancers parted easily when they saw and recognised him. He managed to catch a glimpse of the three familiar people before they disappeared outside the door that confirmed it was Jocelyn's children.

He then realised, watching from nearby two male shadowhunters. Through the darkness he could see circular marks on their neck.  
Valentine's men.  
His alpha growled at the thought of two unknown alphas trespassing. For all he knew, they could be trying to overpower an omega whilst doing Valentine's dirty work. He sent a quick text to Dot, who was close with the Fray's, before going to throw the uninvited Circle members out.

He had managed to sneak up pretty easily, and Magnus heard them mentioning Jocelyn's children. This could only mean one thing. Trouble.

**Author's Note:**

> Hope you liked it. :)  
> If you did, leave a kudos and/or comment, they're a great motivator  
> Feedback and suggestions are also welcome <3  
> Any questions, how was it?  
> 


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